clarnibass
Aluminum
- Joined
- Dec 23, 2015
Hi
Before I go through the hassle of going to a motor specialist...
This is from an Emco lathe (photos attached). It's a 3-phase, 2-speed, 2pole/4pole motor. For some reason the plate says the speeds are 1300/2700... I'd expect it to be exactly half/double but maybe just an approximate spec(?).
Specs:
380V
0.52/0.81 kW
△/YY
1300/2700 1/min
2.85/2.1 A
50 Hz
First thing, I was told (at the Emco group) that on the Emco 2-speed motor, high speed is triangle (delta) connection and low speed is star connection. Looking at the plate now, it seems the opposite? I think the YY means double star and the triangle means delta? I assume it is written this way the same as all other specs (left side is specs for low speed, right side for high speed)?
Second thing, I operate the lathe with a VFD (1-phase input to 3-phase output), since the original switch board is missing and I don't have 3-phase mains right now (I actually do, but can't wire it there right now).
It was working with a very old VFD for a long time, it was defective so I replaced it (this fixed the main issues with the old one).
The previous owner said it is connected on the high speed. I'm measuring spindle speeds with the way it's connected right now and I get pretty close to the low speeds (just slightly more which I understand is normal).
According to the Emco group, the motor has six wires. For delta/triangle wiring, there are three wires going to the VFD and the other three wired together between themselves, but to nothing else. Star wiring would be the other three wires to the VFD (those that are wired to themselves in the delta wiring), and the other three wires isolated each separately, not wired to anything.
So the question is, am I right about the wiring being reversed i.e. triangle/delta for low speed and star (or double star) for high speed? The alternative is that I'm doing something wrong with the VFD, but it does say 50Hz output.
Thanks very much
Nitai
Before I go through the hassle of going to a motor specialist...
This is from an Emco lathe (photos attached). It's a 3-phase, 2-speed, 2pole/4pole motor. For some reason the plate says the speeds are 1300/2700... I'd expect it to be exactly half/double but maybe just an approximate spec(?).
Specs:
380V
0.52/0.81 kW
△/YY
1300/2700 1/min
2.85/2.1 A
50 Hz
First thing, I was told (at the Emco group) that on the Emco 2-speed motor, high speed is triangle (delta) connection and low speed is star connection. Looking at the plate now, it seems the opposite? I think the YY means double star and the triangle means delta? I assume it is written this way the same as all other specs (left side is specs for low speed, right side for high speed)?
Second thing, I operate the lathe with a VFD (1-phase input to 3-phase output), since the original switch board is missing and I don't have 3-phase mains right now (I actually do, but can't wire it there right now).
It was working with a very old VFD for a long time, it was defective so I replaced it (this fixed the main issues with the old one).
The previous owner said it is connected on the high speed. I'm measuring spindle speeds with the way it's connected right now and I get pretty close to the low speeds (just slightly more which I understand is normal).
According to the Emco group, the motor has six wires. For delta/triangle wiring, there are three wires going to the VFD and the other three wired together between themselves, but to nothing else. Star wiring would be the other three wires to the VFD (those that are wired to themselves in the delta wiring), and the other three wires isolated each separately, not wired to anything.
So the question is, am I right about the wiring being reversed i.e. triangle/delta for low speed and star (or double star) for high speed? The alternative is that I'm doing something wrong with the VFD, but it does say 50Hz output.
Thanks very much
Nitai